briannacamille briannacamille
  • 11-07-2014
  • Mathematics
contestada

How do you factor this 8x^2+2x-21=0

Respuesta :

Pulkit
Pulkit Pulkit
  • 11-07-2014
Solve it like this.. 
8x^2+2x-21=0
8x^2 + 14x - 12x -21=0
2x(4x+7) -3(4x+7) = 0
(4x+7)(2x - 3)=0

So factor 1 is 4x +7 =0 
i.e. x=-7/4

Factor 2 is 2x -3 =0
i.e x=3/2
Answer Link
Lilith
Lilith Lilith
  • 11-07-2014
[tex]8x^2+2x-21=0 \\ \\ 8x^2+2x + 12x -12x-21=0\\\\8x^2+ 14x -12x-21=0 \\ \\ 2x(4x+7)-3(4x+7)=0\\\\(4x+7)(2x-3)=0[/tex]

[tex]4x+7=0 \ \ or \ \ 2x-3 =0 \\\\4x=-7\ \ or \ \ 2x=3\\\\x=\frac{-7}{4}\ \ or \ \ x=\frac{3}{2}[/tex]




Answer Link

Otras preguntas

5^2+2[73-(4*5)]....HELP
What is the estimate of 212,514+396,705
angie baked 100 cookies and 20 brownies. she wants to split them into equal groups for the bake sale. Each group must have the same number of cookies and brow
what is the opposite of 3,7.5, and -2 2/3?
Rates are often used to describe how quickly something is moving or changing. a. A wildfire spreads at a rate of 1000 acres per day. How many acres will the
What most affected ancient West African trade?A.Lack of transportationB.natural landformsC.Limited resources for tradeD.too many merchants
how to work problem 6=a/4+2
How many hundredths are in 45.972
what is 0.800 rounded to nearest tenth
Rafael counted a total of 40 white cars and yellow cars there were nine times as many white cars and yellow cars how many white cars did Rafael count